Home > Publications database > Theory of the rippling instability in toroidal devices |
Book/Report | FZJ-2018-02503 |
1985
Kernforschungsanlage Jülich, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/18216
Report No.: Juel-1992
Abstract: The theory of the rippling instability is developed for axisymnetric toroidal plasmas including ion viscosity and parallel electron heat conduction, but assuming that the growth rate is small compared to the wave angular frequency $\omega_{o}$ = (1 + 1.71 $\eta_{e}) \omega^{*}_{e} \cdot \omega^{*}_{e}$ is the electron diamagnetic frequency and $\eta_{e}$ = (dlnT$_{e}$/dr) / (dlnN/dr). Three (in)stability regions must be considered, viz. (c$_{i}$/R$\omega_{o})^{2}$ < 0.12 where cylindrical effects dominate and the plasma is stable ; 0.12 < (c$_{i}(R \omega_{o})^{2}$ 2 < 0.26 q$^{2}$ where the magnetic drift destabilizes the mode ; and 0.26 q$^{2}$ < (c$_{i}/R\omega_{o})^{2}$ where the plasma is stable again. (The numerical values are given for $\eta_{e}$e = $\eta_{i}$ = 2 and T$_{e}$ = T$_{i}$). Parallel electron heat conduction is stabilizing but ion viscosity broadens the instability domain. Under certain conditions, an important top-bottom asymmetry of the density fluctuation spectrum may arise.
The record appears in these collections: |